Field of the Invention
The present invention relates to interrupt systems generally and more especially to a priority interrupt circuit for disconnecting a first audio frequency source from an electroacoustic transducer and connecting a second audio frequency source thereto when that second source becomes active.
Citizens band mobile transceivers have become quite popular, however their use does present some problems to the user. Such citizen band transceivers are normally installed in a vehicle having one or more independent sources of audio entertainment such as a broadcast receiver or tape deck and when preparing to transmit the user must turn down the volume on such audio entertainment devices or turn them completely off prior to his transmission to prevent a confused transmission. Also, incoming signals on the citizens band receiver may be partially or completely missed by the user when both audio sources are operating at the same time. In general, the entertainment audio source while desired, presents difficulties and possible confusion for the citizens band user.
A certain reduction in the hand switching operations required in radio transmission has been achieved by employing voice operated relays. Such voice operated relays are generally employed in fixed based amateur radio work and are employed only to the extent that they replace the typical push-to-talk switch and additionally include circuitry for rendering the relay inoperable so long as incoming signals are present. Due to the noise involved in a mobile environment, the use of such voice operated relays therein would be severely limited.